Diluent/Medication Mixing Syringe Assembly

ABSTRACT

A diluent/medication mixing syringe assembly is described which includes a cannula which extends through a syringe plunger assembly into a reservoir of the syringe assembly. The cannula facilitates injection of a diluent, medication or other fluid into the fluid reservoir of the syringe assembly immediately prior to use for mixing with a medication in the reservoir. In one embodiment, a mixing element is secured to a distal end of the cannula within the reservoir to improve mixing efficiency.

This application claims priority from U.S. Provisional Application Ser.No. 61/101,410 which was filed on Sep. 30, 2008 and is incorporatedherein in its entirety by reference.

BACKGROUND

1. Technical Field

The present disclosure relates generally to syringes and, moreparticularly, to a syringe including a cannula for delivering a diluentor additional medication into the syringe.

2. Background of Related Art

Syringe assemblies which include two chambers for separately storing adiluent and a medication are well known in the art. Typically,multi-chamber syringes which separately store a diluent and a medicationare required with medications which are poorly soluble or insoluble inan agueous solution, medications which lack sufficient physical orchemical stability when stored for a prolonged period of time, ormedications which include active ingredients which undergo degradationdue to interaction with a suspension medium. Such medications aretypically stored in a syringe assembly in a dry, lyophilized stateseparate from a diluent.

Although multi-chamber syringes have proven effective for mixingmedications in powder form with a diluent immediately prior to injectioninto a venous catheter or related device, such syringes typically arecomplex and, thus, are expensive to manufacture.

Accordingly, a continuing need exists in the medical arts for a syringeassembly which has the capability of mixing a diluent with a medicationimmediately prior to injection, which is less complex and providesimproved mixing capabilities.

SUMMARY

A diluent/medication mixing syringe assembly is disclosed which includesa syringe body having an open proximal end and a fluid outlet on adistal end and a plunger assembly including a plunger body and a plungerhead supported on a distal end of the plunger body. The plunger head isslidably and sealingly engaged with an inner wall of the syringe body todefine a reservoir in the distal end of the syringe body. A cannula issupported on and extends through the plunger assembly. The cannuladefines a longitudinal channel which extends through the plungerassembly into the reservoir. In one embodiment, the plunger rod and theplunger head define a longitudinal bore which is dimensioned to receivethe cannula. The cannula can be slidably positioned within thelongitudinal bore such that the distal end of the cannula is movableaxially within the reservoir. The cannula can also be rotatablypositioned within the longitudinal bore.

In one embodiment, a mixing element is supported on the distal end ofthe cannula within the reservoir. The mixing element can include atleast one orifice which extends through the mixing element and isconfigured to cause turbulence within the reservoir when the cannula ismoved axially and/or rotated. The at least one orifice can include aplurality of orifices.

In one embodiment, the proximal end of the cannula includes an adaptorwhich is configured to releasably engage a supply of fluid. The adaptorcan be a female luer type connector.

The syringe assembly can include a sealing member positioned within thelongitudinal bore of the plunger rod about the cannula. In oneembodiment, the cannula is separable from the syringe assembly and theseal member is configured to seal the longitudinal bore of the plungerassembly when the cannula is separated.

In one embodiment, a male luer connector is positioned on the distal endof the syringe body about the fluid outlet.

A method of mixing a diluent (or additional medication) with amedication in a syringe assembly is also disclosed. The method includesthe steps of i) providing a syringe assembly including a syringe bodyand a plunger assembly wherein the syringe body has an open proximal endand a fluid outlet disposed in the distal end, the plunger assemblyincludes a plunger body and a plunger head supported on a distal end ofthe plunger body, the plunger head being slidably and sealingly engagedwith an inner wall of the syringe body and defining a reservoir with thesyringe body in a distal end of the syringe body, and a cannulaextending through the plunger assembly, the cannula defining alongitudinal channel disposed within the reservoir; ii) providing amedication within the reservoir; and iii) introducing a diluent oradditional medication into the reservoir via the cannula. In oneembodiment, the step of providing a syringe assembly includes providinga mixing element on the distal end of the cannula, wherein the methodfurther includes the step of moving the mixing element within thereservoir to mix the diluent (or additional medication) and themedication. In one embodiment, the medication is in powder form. In oneembodiment, the method includes the step of disconnecting the cannulafrom the syringe assembly after the step of moving the mixing element.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the presently disclosed diluent/medication mixingsyringe assembly are disclosed herein with reference to the drawings,wherein:

FIG. 1 is a side perspective view from the distal end of one embodimentof the presently disclosed diluent/medication mixing syringe assembly;

FIG. 2 is a side perspective exploded view from the distal end of thediluent/medication mixing syringe assembly shown in FIG. 1;

FIG. 3 is a side perspective view from the distal end of thediluent/medication mixing syringe assembly shown in FIG. 1 illustratingthe distal end of the plunger assembly and mixing disc in phantom;

FIG. 4 is an enlarged perspective view of the distal end of thediluent/medication mixing syringe assembly shown in FIG. 3 illustratingthe distal end of the plunger assembly and mixing disc in phantom;

FIG. 5 is a side cross-sectional view of the syringe assembly shown inFIG. 1 during movement of the mixing disc within the reservoir with theplunger assembly in a retracted position;

FIG. 6 is a side cross-sectional view of the syringe assembly shown inFIG. 1 with the plunger assembly in an advanced position; and

FIG. 7 is an enlarged cross-sectional view of the distal end of theplunger assembly.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the presently disclosed diluent/medication mixing syringeassembly and its method of use will now be described in detail withreference to the drawings wherein like reference numerals designateidentical or corresponding elements in each of the several views. Inthis description, the term proximal is generally used to indicate therelative nearness of a referenced item to a user of the device and theterm distal is used to indicate the relative remoteness of a referenceditem to a user of the device.

FIGS. 1-7 illustrate one embodiment of the presently discloseddiluent/medication mixing syringe assembly shown generally as 10.Briefly, referring to FIGS. 1 and 2, syringe assembly 10 includes asyringe body 12, a plunger assembly 14, a cannula 16 and a mixingelement 18 (FIG. 2). Plunger assembly 14 includes a plunger body 20 anda plunger head 22 which is secured to a distal end 20 a of plunger body20. Plunger head 22 is slidably positioned within syringe body 12 todefine a reservoir 24 (FIG. 5) within the distal end of syringe body 12as will be discussed in further detail below.

Syringe body 12 has an open proximal end 12 a dimensioned to slidablyreceive plunger body 20 and a distal end 12 b defining a fluid outlet26. A gripping flange 28 is positioned about proximal end 12 a ofsyringe body 12. A male luer connector 30 or related structure is formedabout fluid outlet 26 on distal end 12 b of syringe body 12. A cap (notshown) is provided to seal fluid outlet 26 prior to use of syringeassembly 10.

Referring also to FIGS. 2-5, plunger body 20 has a proximal end whichincludes a finger engagement member 32 and a distal end adapted toreceive plunger head 22. In one embodiment, the distal end of plungerbody 20 includes a stepped portion 34 defining an annular recess 36dimensioned to receive a proximal annular rib 38 (FIG. 5) formed onplunger head 22. Plunger head 22 is formed of a resilient material,e.g., rubber, which is stretched over stepped portion 34 such thatannular rib 38 is received within annular recess 36 to secure plungerhead 22 onto the distal end of plunger body 20. Alternatively, plungerhead 22 and plunger body 20 may have a variety of differentconfigurations for securing plunger head 22 to plunger body 20. Theexternal surface of plunger head 22 includes one or more ribs 40, e.g.,three. Ribs 40 are dimensioned to slidably and sealingly engage an innerwall 42 (FIG. 5) of syringe body 12. Reservoir 24 is defined between adistal face 22 a of plunger head 22 and a distal end 42 a (FIG. 5) ofinner wall 42 of syringe body 12.

Referring to FIG. 5, plunger body 20 defines a longitudinal bore 46which extends the entire length of body 20. Plunger head 22 also definesa bore 48 which is axially aligned with bore 46. Bores 46 and 48 aredimensioned to slidably receive cannula 16 as will be discussed infurther detail below.

Cannula 16 is substantially rigid and defines a longitudinal channel 21.Cannula 16 is slidably positioned through bores 46 and 48 of plungerbody 20 and plunger head 22, respectively. A distal end 16 a of cannula16 is movably positioned within reservoir 24 at a position distally ofplunger head 22. Mixing element 18 includes a central bore 50 (FIG. 2).Distal end 16 a of cannula 16 is received and secured within centralbore 50 of mixing element 18 using any known fastening technique, e.g.,adhesives, crimping, welding, etc., such that axial and/or rotationalmovement of cannula 16 effects corresponding axial and/or rotationalmovement of mixing element 18. A proximal end 16 b of cannula 16includes an adaptor 52 which is configured to releasably engage a supplyof diluent. Adaptor 52 may include a female luer type connector or likestructure. Although not shown, the adaptor 52 may releasably receive acap (not shown) for sealing proximal end 16 b of cannula 16.

As discussed above, mixing element 18 is secured to the distal end ofcannula 16. In one embodiment, mixing element 18 is disc-shaped andincludes one or more orifices 56 which extend through mixing element 18.When cannula 16 is moved axially to move mixing element 18 axiallywithin reservoir 24 (FIG. 5), turbulence is created within the mixturelocated within reservoir 24 to improve the mixing efficiency of themedication and the diluent. In one embodiment, orifices 56 define axeswhich are angled with respect to a longitudinal axis of cannula 16 suchthat axial movement of mixing element 18 causes the mixture withinreservoir 24 to swirl.

Referring to FIG. 7, a sealing member 60 is supported withinlongitudinal bore 46 of plunger body 20. As illustrated, bore 46 mayinclude a stepped portion 46 a which receives sealing member 60. In oneembodiment, sealing member 60 has a proximal end 60 a which includes aninwardly extending annular rib which slidably and sealingly engages anouter surface of cannula 16. Sealing member 60 can be formed of aresilient material which closes or seals bore 46 of plunger body 20 inthe event cannula 16, or a proximal portion thereof, is separated fromsyringe assembly 10. In that respect, cannula 16 may include a frangibleor weakened portion 70 which allows separation of the proximal portionof cannula 16 from the distal portion of cannula 16 upon application ofa predetermined axial or torsional force on the proximal end of cannula16. The predetermined force should be selected to prevent inadvertentseparation of the distal and proximal portions of the cannula whilefacilitating separation by medical personnel. Such predetermined forcecan be from about two to about five pounds.

Referring to FIGS. 3-6, syringe assembly 10 may be provided with amedication in reservoir 24 which may be in powder form. Alternatively,medication can be drawn into reservoir 24 using known techniques. Priorto use, a cap is provided over fluid outlet 26 and over proximal end 16b of cannula 16. In use, with a medication positioned within reservoir24, and a cap (not shown) secured to male luer adaptor 30 over fluidoutlet 26, the cap (not shown) over proximal end of cannula 16 isremoved. Next, a diluent (or additional medication) is introducedthrough cannula 16 into reservoir 24. Then, adaptor 30 is resealed andcannula 16 is moved axially and/or rotated to move mixing element 18within reservoir 24 to effectuate mixing of the medication and thediluent (or additional medication). In one embodiment, as discussedabove, the proximal portion of the cannula 16 can be separated from thedistal portion of the cannula when adequate mixing has been affected.Thereafter, as shown in FIG. 6, the cap (not shown) over fluid outlet 26can be removed and plunger assembly 14 can be actuated to dispense themixture within reservoir 24 through outlet 26.

It will be understood that various modifications may be made to theembodiments disclosed herein. For example, a variety of different sealconfigurations can be used to seal about the cannula. Therefore, theabove description should not be construed as limiting, but merely asexemplifications of preferred embodiments. Those skilled in the art willenvision other modifications within the scope and spirit of the claimsappended hereto.

1. A diluent/medication mixing syringe assembly comprising: a syringebody having an open proximal end and a fluid outlet on a distal end; aplunger assembly including a plunger body and a plunger head supportedon a distal end of the plunger body, the plunger head slidably andsealingly engaging an inner wall of the syringe body, the plunger headand syringe body defining a reservoir in the distal end of the syringebody; and a cannula supported on and extending through the plungerassembly, the cannula defining a longitudinal channel which extendsthrough the plunger assembly into the reservoir.
 2. The syringe assemblyaccording to claim 1, wherein the plunger body and the plunger headdefine a longitudinal bore which is dimensioned to receive the cannula.3. The syringe assembly according to claim 2, wherein the cannula isslidably positioned within the longitudinal bore such that the distalend of the cannula is movable axially within the reservoir.
 4. Thesyringe assembly according to claim 3, wherein the cannula is rotatablypositioned within the longitudinal bore.
 5. The syringe assemblyaccording to claim 3, further including a mixing element supported onthe distal end of the cannula.
 6. The syringe assembly according toclaim 5, wherein the mixing element includes at least one orifice whichextends through the mixing element, the at least one orifice beingconfigured to cause turbulence within the reservoir when the cannula ismoved axially.
 7. The syringe assembly according to claim 6, wherein theat least one orifice includes a plurality of orifices.
 8. The syringeassembly according to claim 1, wherein the proximal end of the cannulaincludes an adaptor which is configured to releasably engage a supply offluid.
 9. The syringe assembly according to claim 8, wherein the adaptoris a female luer type connector.
 10. The syringe assembly according toclaim 9, further including a sealing member positioned within thelongitudinal bore of the plunger body about the cannula.
 11. syringeassembly according to claim 10, wherein the sealing member is fanned ofa resilient material which is configured to seal the longitudinal boreupon removal of at least a proximal portion of the cannula from thelongitudinal bore.
 12. The syringe assembly according to claim 11,wherein the cannula includes a weakened portion which facilitatesseparation of the proximal portion of the cannula from a distal portionof the cannula upon application of a predetermined force on the cannula.13. The syringe assembly according to claim 12, wherein thepredetermined force is from about two pounds to about five pounds. 14.The syringe assembly according to claim 13, further including a maleluer connector positioned on the distal end of the syringe body aboutthe fluid outlet.
 15. A method of mixing a diluent with a medication ina syringe assembly, the method comprising the following steps: providinga syringe assembly including a syringe body and a plunger assembly, thesyringe body having an open proximal end and a fluid outlet disposed inthe distal end, the plunger assembly including a plunger body and aplunger head supported on a distal end of the plunger body, the plungerhead slidably and sealingly engaging an inner wall of the syringe bodyand defining a reservoir with the syringe body in a distal end of thesyringe body, and a cannula extending through the plunger assembly, thecannula defining a longitudinal channel disposed having a distal enddisposed within the reservoir; providing a medication within thereservoir; and introducing a diluent into the reservoir through thecannula.
 16. The method according to claim 15, wherein the step ofproviding a syringe assembly includes providing a mixing element on thedistal end of the cannula, and further including the step of moving themixing element within the reservoir to mix the diluent and themedication.
 17. The method according to claim 16, wherein the medicationis in powder form.
 18. The method according to claim 16, furtherincluding the step of disconnecting the cannula from the syringeassembly after the step of moving the mixing element.